Mounting and Commissioning
3.3 Commissioning
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
446
Note
If operation with capacitive load is not possible, then load points in the underexcited range can be achieved by
changing the polarity of the current transformer connections (address 210). Thereby the characteristics of the
underexcitation protection are mirrored around the zero point. It must be noted that the reverse power protec-
tion must be set to OFF (address 3101) as its characteristic is also mirrored from the motor into the generator
range.
Since the protective device shows each load level through the operational measured values, it is not necessary
to approach the underexcitation limit line.
Checking the Directional Function of the Overcurrent Time Protection
When the polarity of the connections is checked, the direction of the protection function I>> (Section 2.9) is
unambiguously determined by the definition of the reference arrow in the protection device. When the genera-
tor produces an active power (operational measured value P is positive), and address 1108 ACTIVE POWER
is set to Generator, the network is in the forwards direction.
In order to exclude accidental misconnections, it is recommended to carry out a check with a low load current.
Proceed as follows:
• Set the directional high current stage 1301 O/C I>>to Block relay and the pickup value I>> (parameter
1302) to the most sensitive value (= 0.05A with a rated current of 1A and 0.25 A with a rated current of 5 A).
• Increase the load current (ohmic, or ohmic inductive) above the pickup value, and as soon as the pickup
indications (No. 1801 to 1803) appear, query the indications 1806 „I>> forward“ and 1807 „I>>
backward“.
• Compare the indicated direction with the setpoint (setting value and address 1304 Phase Direction). In
the standard application with terminal-side current transformers, address 1304 Phase Direction must
be set to reverse and indication „I>> forward“ (No. 1806).
• Reset the pickup value in address 1302 back to the original value and the protection function in address
1301 O/C I>> to ON.
Checking the Sensitive Earth Current Protection IEE-B
Set the sensitive earth current protection IEE-B to Block relay at address 5401.
With the generator stationary, a current (determined by the number of test turns among others) has to be in-
jected over the test winding of the shaft current transformer and pickup of the protective function has to be
checked using the default value (test current should be twice the value). This is primarily a wiring check and an
additional check of the function's pickup behaviour and the correct allocation (signalling).
The subsequent primary tests have to be conducted after commissioning the „synchronization“.
Proceed as follows:
• Synchronise the generator with the power grid and run it under load.
• Trigger a fault record in DIGSI and determine the predominant frequency component using SIGRA. Depend-
ing on the connection, evaluate the fault record track of input I
ee1
or I
ee2
. Depending on the outcome, select
the appropriate measurement method at address 5406. It is possible to check all 3 variants (Fundamental,
3. Harmonic and 1. and 3. Harm.) and subsequently select the method that has yielded the best
result.
• After setting the measurement method, read the fault current out of the operational measured values.
• Calculate the pickup value of the function by multiplying the fault current with a safety factor (min. 1.5) and
then enter it in address 5402.
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